The present invention relates to connectors. More particularly, the present invention relates to a connector assembly employing a novel door assembly.
Communication system and/or network efficiency is directly dependent upon the integrity of the connector scheme employed. Such connector schemes include, for example, standard interfaces for equipment/user access (outlet connector), transmission means (horizontal and backbone cabling), and administration/distribution points (cross-connect and patching facilities). Regardless of the type or capabilities of the transmission media used for an installation, the integrity of the cabling infrastructure is only as good as the performance of the individual components that bind it together.
By way of example, a non-standard connector or pair scheme may require that work area outlets be rewired to accommodate a group move, system change, or an installation with connecting hardware whose installed transmission characteristics are compatible with an existing application but are later found to have inadequate performance when the system is expanded or upgraded to higher transmission rates. Accordingly, connecting hardware without properly qualified design and transmission capabilities, can drain user productivity, compromise system performance and pose a significant barrier to new and emerging applications.
Reliability, connection integrity and durability are also important considerations, since cabling life cycles typically span periods of ten to twenty years. In order to properly address specifications for, and performance of telecommunications connecting hardware, it is preferred to establish a meaningful and accessible point of reference. The primary references, considered by many to be the international benchmarks for commercially based telecommunications components and installations, are standards ANSI/TIA/EIA-568-A (/568) Commercial Building Telecommunications Cabling Standard and 150/IEC 11801 (/11801), generic cabling for customer premises. Among the many aspects of telecommunications cabling covered by these standards are connecting hardware design, reliability and transmission performance. Accordingly, the industry has established a common set of test methods and pass/fail criteria on which performance claims and comparative data may be based.
To determine connecting hardware performance in a data environment, it is preferred to establish test methods and pass/fail criteria that are relevant to a broad range of applications and connector types. Since the relationship between megabits and megahertz depends on the encoding scheme used, performance claims for wiring components that specify bit rates without providing reference to an industry standard or encoding scheme are of little value. Therefore, it is in the interest of both manufacturers and end users to standardize performance information across a wide range of applications. For this reason, application independent standards, such as /568 and /11801, specify performance criteria in terms of hertz rather than bits. This information may then be applied to determine if requirements for specific applications are complied with. For example, many of the performance requirements in the IEEE 802.3i(10BASE-T) standard are specified in megahertz, and although data is transmitted at 10 Mbps for this application, test "frequencies" are specified in the standard (as high as 15 MHZ). Transmission parameters defined in /568 and /11801 for twisted-pair connectors include attenuation, near-end crosstalk (NEXT) and return loss. The net effect of these parameters on channel performance may be expressed in signal-to-noise ratio (SNR). For connecting hardware, the parameter that has been found to have the greatest impact on SNR is near-end crosstalk.
Several industry standards that specify multiple performance levels of twisted-pair cabling components have been established. For example, Category 3, 4 and 5 cable and connecting hardware are specified in both /568 and /11801, as well as other national and regional specifications. In these specifications, transmission requirements for Category 3 components are specified up to 16 MHZ. Transmission requirements for Category 4 components are specified up to 20 MHZ. Transmission requirements for Category 5 components are specified up to 100 MHZ. The category 5 classification defines the most severe transmission requirements specified by national and international standards for unshielded and screened twisted-pair cabling.
In order for a twisted-pair connector to be qualified for a given performance category, it must meet all applicable transmission requirements regardless of design or intended use. The challenge of meeting transmission criteria is compounded by the fact that connector categories apply to worst case performance. For example, a work area outlet that meets Category 5 NEXT requirements for all combinations of pairs except one, which meets Category 3, may only be classified as a Category 3 connector (provided that it meets all other applicable requirements).
It is recognized that there are numerous ways of achieving electrical balance for connecting hardware of the type that is disclosed by the present invention. Several Category 5 type outlet connectors are presently commercially available. These include Systemax SCS Category 5 Products from AT&T Network Systems, DVO Plus and BIX Plus from Northern Telecom and the Category 5 ACO outlet from AMP. This list is only exemplary and is not intended to be a complete listing of Category 5 type products that are presently commercially available. Accordingly, there is a continuing need for improved outlet connectors which meet or exceed Category 5 performance requirements in order to satisfy increasing bandwidth requirements of communication systems and networks.
The Systemax SCS Category 5 outlet from AT&T network systems uses a "cross-over lead" concept which achieves a desired level of crosstalk performance without the use of printed wiring boards or other additional components (U.S. Pat. No. 5,186,647 to Denkman et al). This product uses a variation of the well known lead-frame outlet construction that has been in use for many years by numerous companies. Although this approach offers potential cost benefits by minimizing the quantity and types of components in the completed assembly, it is limited in several major respects.
It will be appreciated that other methods of balance compensation exist, such as selective parallel runs of circuit traces either in a side-by-side configuration of overlapping traces placed on adjacent layers of a circuit board. It is also possible to vary trace thickness in order to achieve a degree of inductive balance correction between pairs. Another method is to lay a piece of flexible printed circuit (FPC) on top of an array of contacts. Selected contacts are electrically connected to portions of flexible printed circuit (FPC). Some of these methods are disclosed in U.S. Pat. No. 5,299,956, Brownell. Yet another method of achieving balance between pairs that employs neither lead-frame or printed circuit construction is to selectively twist wire leads that exit the back of a conventional modular outlet. However, each of these methods has its own inherent limitations in terms of repeatability, cost and performance. For example, passive FPC over lead flame designs include drawbacks such as resonating crosstalk. Where twisted wire leads are employed, inconsistency is problematic and cost is high.
An ITT Cannon modular outlet having reduced crosstalk comprises a connector housing with a contact carrier received therein, which supports a plurality of contacts. A hinged termination cover is attached to the housing for terminating a plurality of wires at one end of the contacts. Using the T568A pin/pair scheme defined in standard /568, the R4 contact comprises an insulation displacement terminal connected by a plate to a modular outlet terminal. The T4 contact comprises an insulation displacement (IDC) terminal connected by a lead to a modular outlet terminal. The T1 contact comprises an insulation displacement terminal connected by a plate to a modular outlet terminal. The R1 contact comprises an insulation displacement terminal connected by a plate to a modular outlet terminal. The R3 contact comprises an insulation displacement terminal connected by a lead to a modular outlet terminal. The T3 contact comprises an insulation displacement terminal connected by a plate to a modular outlet termination. The R2 contact comprises an insulation displacement terminal connected by a first lead to a modular outlet terminal. A second lead of the R2 contact extends from one side of the first lead of the R2 contact and terminates in a first plate of the R2 contact. A third lead of the R2 contact extends from the other side of the first lead of the R2 contact and terminates in a second plate of the R2 contact. The T2 contact comprises an insulation displacement terminal connected by a first lead of the T2 contact to a modular outlet terminal. A second lead of the T2 contact extends from one side of the first lead of the T2 contact and terminates in a first plate of the T2 contact. A third lead of the T2 contact extends from the other side of the first lead of the T2 contact and terminates in a second plate of the T2 contact.
The plate of the R4 contact is disposed over the second plate of the R2 contact and the plate of the R1 contact is disposed over the first plate of the R2 contact, with a dielectric sheet disposed therebetween. Accordingly, capacitive coupling is induced or added between the R2 contact and the R4 and R1 contacts. Further, the plate of the T1 contact is disposed above the second plate of the T2 contact and the plate of the T3 contact is disposed above the first plate of the T2 contact, with the dielectric sheet disposed therebetween. Accordingly, capacitive coupling is induced or added between the T2 contact and the T1 and T3 contacts.
It is important to note that these plates are shunt circuits connected to the signal carriers such that electrical current does not pass through the plates in order to allow the signal to pass from input to output. Such passive capacitive plates suffer from the known problem of resonating crosstalk, a phenomena believed to result from signal reflection and/or lack of signal balance.
In general, prior art modular outlets also have the following limitations.
Many prior art modular outlets have IDC terminals sequenced in accordance with the wiring scheme of T568A or T568B of/568. These IDC terminal sequences require that one of the twisted wire pairs be untwisted and split which has a detrimental effect on crosstalk performance.
The prior art modular outlets, when installed into a panel, cannot be stacked side by side. In applications where higher outlet density is required, the prior art arrangements sacrifice space efficiency.
Many prior art modular outlets are installable into proprietary panel openings, which limit the outlets' adaptability to various applications.
The prior art modular outlets must be installed into a panel opening from the rear of the panel. In actual installations, most users prefer to install a terminated outlet from the front of the panel.
Many prior art outlets which employ a termination cap require extensive cable preparation, before a cable can be attached to the termination cap. In general, each twisted pair must be untwisted. Each of the individual wires must be straightened, aligned, and if necessary, trimmed, before the cable can be installed onto a termination cap.
A disadvantage of the ITT outlet is that it requires four discrete housing, components. The living hinge design has the limitations of restricting material selection and compromised mechanical integrity.
Known doors for prior art outlets are generally spring loaded whereby they are not retainable in an open position but only in a closed position. This disadvantage requires a user to use two hands when installing a plug, i.e., one to hold the door open and the other to install the plug.